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From: Vasily Averin <vvs@virtuozzo.com>
To: linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
	NeilBrown <neilb@suse.com>, Waiman Long <longman@redhat.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Oberparleiter <oberpar@linux.ibm.com>
Subject: [PATCH 7/7] sysvipc_find_ipc should increase position index
Date: Fri, 24 Jan 2020 10:03:12 +0300	[thread overview]
Message-ID: <b7a20945-e315-8bb0-21e6-3875c14a8494@virtuozzo.com> (raw)

if seq_file .next fuction does not change position index,
read after some lseek can generate unexpected output.

https://bugzilla.kernel.org/show_bug.cgi?id=206283
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
 ipc/util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ipc/util.c b/ipc/util.c
index 915eacb..7a3ab2e 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -764,13 +764,13 @@ static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
 			total++;
 	}
 
+	*new_pos = pos + 1;
 	if (total >= ids->in_use)
 		return NULL;
 
 	for (; pos < ipc_mni; pos++) {
 		ipc = idr_find(&ids->ipcs_idr, pos);
 		if (ipc != NULL) {
-			*new_pos = pos + 1;
 			rcu_read_lock();
 			ipc_lock_object(ipc);
 			return ipc;
-- 
1.8.3.1


             reply	other threads:[~2020-01-24  7:03 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-24  7:03 Vasily Averin [this message]
2020-01-24 16:26 ` Waiman Long
2020-02-25  6:35   ` Vasily Averin
2020-05-05 16:13 ` Andreas Schwab
2020-05-06  5:03   ` Vasily Averin
2020-05-06  6:25     ` [PATCH] ipc/util.c: sysvipc_find_ipc() incorrectly updates " Vasily Averin
2020-05-06 15:59       ` Waiman Long
2020-05-07 12:29         ` Vasily Averin
2020-05-08  0:02       ` Andrew Morton
2020-05-08  3:36         ` Matthew Wilcox
2020-05-08  6:07           ` Vasily Averin
2020-05-08 10:01             ` Vasily Averin
2020-05-12  9:21               ` Jiri Slaby
2020-05-12 15:45                 ` Vasily Averin

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